Ok, so I am a moron.

I pulled this engine apart back in December and didn't take enough care marking the parts/pieces. Now I am reinstalling everything and I have a wire plug that appears to have nowhere to go.

Will somebody please me?

Here are the "before" pics:









And these are the "after" pics. The wiring plug I have in my hand is the one that I can't seem to find a spot for. Anyone have any thoughts? From the before pics, I'm thinking that it must go somewhere down below the throttle body/intake because I don't see it coming out at all.











And a closeup of the mystery wire:



Any help?

fuel injector?

Thanks, but I already have 4 fuel injectors hooked up. I compared the wires on the FI plugs with this mystery plug and they are all thicker. The wires on the mystery plug are a smaller gauge. Maybe there is a smaller 5th cylinder somewhere (like a 3rd nipple?)

Thanks for the try though.

Sorta looks like the knock sensor plug, mid way down the block in front of the fuel filter.

It's the cold start injector plug, like TNRabbit said.

His Cold Start injector timer as well as the EFI temp sensor are on the LOWER half of the intake which IS in the picture...

Cold start injector plug picture.

If it's grey then it's hanging loose on my motor. never has been hooked up. Zoomed in on your pictures and it is hanging there where the red arrows are.

i have an 89 4runner and when i hooked up all of the electrical after my rebuild i had the same plug left over except my connector looks different. i didn't get labled because it wasn't plugged up to begin with was my final conclusion. the little bit of research i did i decided that it was the egr temp sensor plug for the rec version. i have a blue and white wire and a orange and black wire. i see that you have an egr temp sensor and it is allready plugged up. ????

OK, so there are two votes for it is an unused plug:
PirateFins and Toyaholic

Then there are three folks that think it is the Cold Start Injector plug, but of those three two think the CSI plug goes on the upper half of the intake, and one thinks it goes on the lower half. If it goes on the lower half, where?

Regarding the upper half of the intake: there is only one electrical socket that I can find and there is a black wiring plug in the picture below that I thought would be the one that plugs into that socket. You can see it right above the fuel rail and it is visible in several of the other pictures as well:



To DaveinDenver, I did find one socket midway down the block and I plugged a wiring plug into it. That combination seems right though because they were the only plug and socket of that particular size. This mystery plug is a problem because it could fit any of several of the other sockets. I thought Toyota designed their stuff so that things would only fit one way poke-yoke-style

If it is unused, the engine will probably start and run fine.

If it is used, the engine probably wont start or run fine.

Maybe finish up and turn the key. Might let you know right then and there. Unless someone else thinks a missing sensor wire could cause damage when firing up.

yeah the cold start injector is on the upper intake for sure and i have never seen one that does not have the bulky black square plug. the harness wires usually form to the direction that they originated from. i think you are good.

my guess is the a/c idle up vsv. and it looks like from your before pictures, you dont have one. continue.

Sounds like the consensus is to leave it unplugged? Kinda scary...

ssupercoolss - Is that what you were trying to say too? I don't know if I understand your message completely.

Why is it scary? I showed you in your original picture where it is sitting in your motor unplugged, just like it is sitting in my motor unplugged, and mines been apart 3 times and put back together 3 times all by Certified Toy Mech's. If you could find the right search term you would find your not the first person to ask about it.

Well, I don't have a clue what the plug is, but the inside of it looks pretty dirty in the picture. My guess is that is was never plugged into anything.

Ummm, why does the #1 injector and the #2 injector have different style plugs on them? That looks like an injector plug. Are you sure you have the right plug on the #2 injector?

Definitely not sure - how can I tell for sure?

I couldn't see as clearly as you could I guess. I have studied those pictures and can't seem to see it. I'm not ignoring you, I just want to make sure I get this done right the first time so I am looking at all the options and gathering as many opinions as possible.